Bournemouth are in need of another defender after losing Dean Huijsen to Real Madrid, and Ilya Zabarnyi expected to join Paris Saint-Germain. They will have to turn to other options after their rejection from Bade, though.
Leverkusen, meanwhile, are looking to add another centre-back to help cover for the loss of Jonathan Tah, having already landed Jarell Quansah from Liverpool.
Sunderland, looking to continue their busy summer with an ambitious move for Bade, have already made eight signings this summer. They are also looking to add more defensive reinforcements in the form of Jhon Lucumi from Bologna and attacker Marc Guiu is expected to join on loan from Chelsea.